It’s the same price as Apple Music here in Canada. Is their catalog better/larger? Better service?
Serious question, why would one chose them?
You can find the differences in features between the various online music services on this Wikipedia page:
Comparison of music streaming services - Wikipedia
In that table the two most important columns are Lossless and # of tracks. You can see that the major players have 70M+ tracks, so that shouldn't necessarily be a decider.
But what is important is that Apple currently only has a lossy audio stream, specifically 256 kbps (not shown in that table). There are rumors that Apple may release a lossless service sometime in the near future.
Deezer can stream lossless CD quality (1411 kbps).